Archive for category: RF Radio circuits

Regenerative Receivers Regenerative receivers provide a surprising level of performance with only a handful of components. They excel at receiving amplitude modulated signals from below the AM broadcast band up to the higher short-wave bands above which the superregenerative detector becomes the better choice. Many designs for regenerative receivers are available and most will do […]

The Amazing All-Band Receiver The Amazing All-Band Receiver is basically a diode detector followed by a high-gain audio amplifier. This is not a multi-band receiver; it picks up everything at once! The detector uses a biased Schottky diode for excellent sensitivity and bandwidth; the detector will detect signals from below the AM broadcast band up […]

Cell Phone Helper See the improved circuit below for newer phones. When your cellular phone receives a call, it begins transmitting even before you answer. The circuit shown in fig.1 detects this signal and can operate a variety of devices referred to as "load". For times when a loud beeping is unacceptable, the load […]

Antennas Home-made antennas can greatly improve the performance of AM and FM radios, short-wave receivers, and scanners. If you are a talk-radio fan then experiment with the AM band antennas and you will be able to hear shows from all over the country with surprising clarity. Short-wave receivers are always coping with weak signals and […]

Project Description This circuit is a VHF (Very High Frequency) preamplifier for the band two spectrum tuning approx. 88 – 108 MHz. The 2N3819 FETs are connected in cascode mode in the circuit. The lower one operates in common source mode and the other one operates in common gate mode. The preamplifier provides full high […]

Circuit Project Description The circuit utilizes an 8-pin single chip microcontroller PIC12F509 that is used mostly for low pin count applications with 1K word flash memory and 41 bytes SRAM while having some features like power saving sleep mode and wake-up from sleep on pin change. Explanation An ultra small wireless transmitter TLP434 is being […]

Description: This is an improved IR remote control extender circuit. It has high noise immunity, is resistant to ambient and reflected light and has an increased range from remote control to the extender circuit of about 7 meters. It should work with any domestic apparatus that use 36-38kHz for the IR carrier frequency. Please note […]

This circuit will allow you to turn on any piece of equipment that operates on 115 volts ac. The reciever circuit is based on the Radio Shack infrared receiver module(MOD), part number 276-137. It is also available from some of the other sources listed on my Links page. The MOD accepts a 40khz IR signal […]

Don’t like your little brother’s TV channel selection? Hate the volume your wife sets the stereo at? Want to just annoy someone? This circuit does all that and more by jamming most IR remote signals. The circuit releases a flood of pulsing IR light that confuses the reciever by corrupting the data stream. Circuit diagram […]

Description This circuit is used to relay signals from an Infra Red remote control in one room to an IR controlled appliance in another room. Forward I have seen these devices advertised in magazines, they sell for around ?40-?50 and use radio to transmit between receiver and transmitter. This version costs under ?5 to make […]